Which factors influence incisor position according to Mills and Ballard?

The position of incisors is influenced significantly by the functional and esthetic dynamics of the lips and the relationship it has with the overjet. The upper lip plays a critical role as it interacts directly with the upper incisors, determining their positioning by applying pressure during rest and function. Just as importantly, the lower lip exerts influence on the positioning of the lower incisors, contributing to their angulation and inclination relative to the dental arch. Additionally, the overjet—defined as the horizontal distance between the upper and lower incisors—affects how the lips support and contour the position of these teeth.

In clinical practice, understanding the relationship between these facial structures and the incisors is crucial for achieving balanced and functional occlusion, as well as for aesthetic outcomes. Therefore, the factors of upper lip, lower lip, and overjet provide a comprehensive view of what influences incisor positioning according to the insights of Mills and Ballard.